Filtering patient signal also for ventilation artifacts

Abstract

In embodiments, an external medical device is intended to care for a patient. If it receives an input that signifies that ventilation artifact is present in a signal of the patient, it transmits a corrective signal responsive to the received input. In further embodiments, a patient signal is received, which is generated from a patient while the patient is or was receiving chest compressions at a frequency Fc, and also receiving ventilations at frequency Fv. At least one filter mechanism may be applied to the patient signal to substantially remove artifacts at a) frequency Fc, b) a higher harmonic of frequency Fc, and c) a third frequency substantially equaling frequency Fc plus or minus frequency Fv, while substantially passing other frequencies between them. As a result, the patient signal can be cleaner, for diagnosing the patient's state more accurately.

What is claimed is: 
     
       1. A system for treating a patient, comprising:
 a mechanical chest compression device configured to deliver chest compressions to the patient at a frequency Fc; 
 a ventilator configured to deliver ventilations to the patient at a frequency Fv; and 
 an external device having a housing and a processor within the housing, the processor configured to:
 receive a signal from the patient, and 
 apply at least one filter mechanism to the patient signal to substantially remove from the patient signal artifacts at the frequency Fc, at a higher harmonic of the frequency Fc, and at a third frequency substantially equaling the frequency Fc minus the frequency Fv, while substantially passing other frequencies between the frequency Fc and the higher harmonic, and between the frequency Fc and the third frequency. 
 
 
     
     
       2. The system of  claim 1 , in which
 the patient signal is an ECG signal. 
 
     
     
       3. The system of  claim 1 , in which
 the patient signal is an impedance signal. 
 
     
     
       4. The system of  claim 1 , further comprising:
 an energy storage module within the housing for storing an electrical charge, and 
 a defibrillation port for guiding via electrodes the stored electrical charge to the patient. 
 
     
     
       5. The system of  claim 1 , further comprising:
 a display in connection with the housing. 
 
     
     
       6. The system of  claim 5 , in which
 the processor is further configured to cause the display to present visually to a user the patient signal with the artifacts substantially removed. 
 
     
     
       7. The system of  claim 1 , further comprising:
 a memory, and 
 in which the processor is further configured to store in the memory the patient signal with the artifacts substantially removed. 
 
     
     
       8. The system of  claim 1 , in which
 the filter mechanism substantially rejects additionally at least two more frequencies that are additional higher harmonics of the frequency Fc. 
 
     
     
       9. The system of  claim 1 , in which
 the frequency Fc is looked up from an inputted identification of the mechanical chest compression device. 
 
     
     
       10. The system of  claim 1 , in which
 an indication of the frequency Fc is received by the processor. 
 
     
     
       11. The system of  claim 1 , in which
 the processor is further configured to detect the chest compressions. 
 
     
     
       12. The system of  claim 1 , in which
 the frequency Fv is looked up from an inputted identification of the ventilator. 
 
     
     
       13. The system of  claim 1 , in which
 an indication of the frequency Fv is received by the processor. 
 
     
     
       14. The system of  claim 1 , in which
 the processor is further configured to detect the ventilations. 
 
     
     
       15. The system of  claim 1 , in which
 the filter mechanism comprises a comb filter, a plurality of notch filters, or both. 
 
     
     
       16. The system of  claim 15 , in which
 the filter mechanism has a Q value of no less than 4. 
 
     
     
       17. The system of  claim 15 , in which
 the plurality of notch filters has a 3 dB notch width of no more than approximately 0.5 Hz. 
 
     
     
       18. The system of  claim 1 , in which
 the filter mechanism includes a non-adaptive filter. 
 
     
     
       19. The system of  claim 1 , in which
 the processor is configured to apply the filter mechanism responsive to an input by a user. 
 
     
     
       20. The system of  claim 1 , in which
 the processor is further configured to monitor an impedance signal of the patient, and to further detect return of spontaneous circulation by applying a signal-averaging filter to the impedance signal.